Photographic printer having air flow film tautening mechanism



June 6, 1950 w. H. RICHARDS 2,510,142

PHOTOGRAPHIC PRINTER HAVING AIR FLow FILM TAUTENING MECHANISM Filed March 7. 1947 7 sheets-sheet 1 June 6, 1950 w H. RICHARDS 2,510,142

PHOTOGRAPHI PRINTER HAVING AIR FLOW FILM TAUTENING MECHANISM Filed March 7, 1947 '7 Sheets-Sheet 2 I N VEN TOR.

W. H. RICHARDS PHOTOGRAPHIC PRINTER HAVING AIR FL `lune 6, 1950 FIL TAUTENING MECHANISM 7 Sheets-Sheet i5 Filed March 7. 1947- mi V fw... man W gw M MM WMZ June 6, 1950 w. H. RICHARDS 2,510,142

PHoToGRAPHc PRINTER HAVING AIR FLow FILM TAUTENING MECHANISM Filed ua'r'h 7, 1947 7 sheets-sheet 4 INVENTOR.

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JUN 5 1950 w. H. RICHARDS 2,510,142

v PHQIOGRAPHIC PRINTER HAVING AIR FLow FILM TAUTENING MECHANISM Filed lrch 7, l1947 7 Sheets-Sheet 5 June 6,V 1950 w. H. RICHARDS 2,510,142

PHOTOGRAPHIC PRINTER HAVING AIR FLow FILM TAUTENING MECHANISM Y Filed :Maren 7. 1947 Y -7 sheets-sheet s [lilll v//V inne/Vif!- June 6, 1950 w. H. RICHARDS 2,510,142

PHOTOGRAPHIC PRINTER HAVING AIR FLOW FILM TAUTENING MECHANISM Filed March 7, 1947 7 Sheets-Sheet 7 Patented June 6, 1950 OFFICE PHOTOGRAPHIC PRINTER HAVING AIR FLOW FILM TAUTENING MECHANISM William H. Richards, Dayton, Ohio Application March 7., 1947, Serial No. 733,214

10 Claims.` (Cl. 95-75) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Goverment for governmental purposes without payment to me of any royalty thereon,

This invention relates to a photographic print- Y I ing machine of the continuous type.

An important object of the invention is to provide, in a machine of this kind, mechanism for rapidly making and maintaining perfect and uniform contact between the photographic film, the sensitized print paper and the printing glass.

More specifically the object is to provide means for maintaining a volume of air under a predetermined pressure over the surface of the print paper, the air owing continuously from the middle of the sheet toward the edges thereby to smooth `out the lm and print paper While printing is being effected.

Another object is to so contro1 the air flow that no reversal in direction of flow may occur to ruffle the exposed print or interfere with the advancing print paper.

Other objects and advantages will appear as the invention is described in detail and reference is had to the drawing,

Wherein:

Fig. 1 is a front elevation of the machine with portions of the framework broken away to show the interior construction;

Fig. 2 is a front elevation of the power operated portion of the machine drawn to a larger scale than shown in Fig. 1;

Fig. 3 is a side elevation of Fig. 2 looking from right to left, a small portion being broken away for clearness;

Fig. 4 is an enlarged fragmentary axial section through the cylinder, piston, valve, platen, printing plate and printing plate frame;

Fig. 4a is an enlarged fragmentary view of the valve operating connection;

Fig. 4b is a schematic view of the print paper feed mechanism;

Fig. 5 is a side elevation of the exposure housing and its associated parts;

Fig. 5a is an enlarged fragmentary view of the film guide roller;

Fig. 6 is a fragmentary section taken at 6--6 of Fig. 5 showing how a light seal is maintained in the exposure housing;

Fig. '7 is another side elevation of the exposure housing with its associated parts in a different position; and

Fig. 8 is a wiring diagram showing the arrangement of the manual and the automatic switches which determine which of the exposure lights are to be used, and the arrangement of the manual and automatic switches which control the starting and stopping of the motor at a preselected point in its cycle.

Like reference characters refer to like parts throughout the drawings.

The framework I0 of the machine is composed of three main parts, a base I2, a hollow pedestal I4 and a box-like table I6 extending horizontally across the top of the pedestal (see Fig. 1). The lesser units of the machine are carried by these main parts.

Mounted on the base I2 is an electric motor I8 which drives through a speed reducing gear box 20 (see Figs. 2 and 3) to a relatively low-speed main power shaft 22 which has its axis normal to the motor axis.

Freely rotatable on the main power shaft 22 is a crank disc 26 which carries a crank pin 24. A cam 28 having an operating lobe 29 is secured to the crank shaft 22 to rotate in unison therewith. The function of cam 28 is to operate a mercury switch 3i) (see Figs. 2 and 8) for connecting a power source 3i to the motor I8, the cam 28 being arranged to open the circuit and stop the motor I8 when the crank disc 26 is at top center. A manual switch 32 controls a parallel circuit from the power source 3l to the motor IB (see Fig. 8), whereby, when the manual switch 32 is closed, the motor I8 will operate continuously, while if the manual switch 32 is open, the motor will be stopped at top center of the crank disc 26. A master switch 2l is provided to disconnect the entire circuit.

A short cam lobe 33 and a longer cam lobe 34 are formed on the periphery of the crank disc 26 for respectively operating two mercury switches 35 and 36 which control the exposure lamps. A double pole double throw manual switch il is provided and electrically connected in the circuit as in Fig. 8, whereby when the switch 4I is thrown in one direction, a circuit will be completed through the mercury switch 35 by the short cam lobe 33, and when the switch 4I is thrown in the other direction, a circuit will be completed through the mercury switch 36 by the long cam lobe 34.

A means for drivably connecting the crank disc 26 to the main power shaft 22 or for releasing it therefrom at the option of the operator is provided. A dog 37 having an operating end 38 is drivably secured to the main power shaft 22 by a key 39. A stub shaft Ill] has rotative bearing in the crank disc 26, the forward end being squared as at 43 to receive a handle 43 which is additionally held on the shaft by a pin 41, the rotation of the shaft being limited to a half turn by pins 42 in the hub oi the handle 48 engaging a pin 44 in the crank disc 26. A hub 46 on the rear end of the shaft [iii may be an integral part of the shaft. Hub i6 is substantially half cut away so as to leave a lug 553, whereby, when the handle Q8 points in the direction of rotation of the main power shaft 22, the operating end 3S of the dog 3l will pass the hub 45 without moving it, but when the handle 423 is made to point oppositely, as shown in Figs. 2 and 3, the operating end 38 will engage the lug 5t and the crank disc 26 will be rotated in unison with the main power shaft 22.

As a means for operating the mercury switch 3S for stopping the motor it when the crank disc is on top center, an arm 52 carries a roller 5&3 which rests on the outer surface of the cam 28. The oneend ofthe arm 52 is supported by a pin 55 in a slot 5t, while the `other -end has a ball and socket rconnection with the switch operating lever 69 of the mercury switch 2id. When the operating lobe 2i? of the cam 2S reaches top center, i. e., ninety degrees clockwise from the position shown, the switch 5:33 will be in the off position. If the manual switch 32 (see Fig. 8) is open when the operating lobe 29 reaches top center, the motor i8 will stop.

The crank pin 2li is fixed in the crank disc 2t, and the lower or crank-bearing end of a main connecting rod 54 is runningly fitted thereto. The upper or wrist pin bearing end of the main connecting rod t4 is runningly fitted over a wrist pin 663 which is carried in a cross head t@ which is slidable vertically in the cross head guides 'IIL Cross headfguides 'it are carried 'by brackets 'i2 which are `in turn supported on a column l@ which extends upward from the top of the gear box 2U for which it forms a closure and rearward as at 7|5'to the back wall of the pedestal i4 to which it may be bolted or secured in any suitable manner.

A cylinder It has a flange o5 (see Fig. l) by which it is secured to the top of the pedestal lli-.3

within the hollow table It. A piston 8@ is slidably fitted into the cylinder it, both cylinder and piston being open top and bottom, the piston, however, having a series of Spokes S2 extending inwardly from its opening to a central hub 84. A ltubular piston rod S5 has its upper end threadedly secured in the central hub S4 (see Fig. l), the lower end being provided with a ball socket 83 (see Fig. 3) which adjustably surrounds a ball 9d carried on a bracket Q2 extending laterally from the cross head 68, whereby rotation of the crank disc 2li moves the piston 8|! up and down.

A large disc valve 94 concentrically covers the upper open side of the piston Bt. Valve 94 has a `stem 96 (see Fig. 4a) which extends downwardly into the tubular member 85 to which it is slidably fitted. An auxiliary cross head 971 which is slidable on the tubular member 86 carries a small wrist pin 98 which extends transversely through the Valve stem 96, the tubular member 86 being provided with a slot I0@ (see Fig. 3) whereby the Valve stem 96 may have relative movement with respect to the tubular member 86. The upper end of the valve stern 96 is apertured for the stem 99 of a ball ISI which is held in a recess |93 in the valve 94 by a Iplate m5, whereby the valve 94 is self-aligning for Contact with its seat `on the top of the piston 80.

The front side of the main connecting rod 64 is channeled as at |02, and a sliding bar IM of rectangular cross section is slidably retained in guide portions of the channel by plates Iit held by screws IUS. An auxiliary connecting rod il@ has the lower end hinged by the screw stud IIE to the sliding bar m4, the upper end being pivoted on the small wrist pin d8. The sliding bar |34 has a small roller |I4 rotatable on a pin I I6 in the lower end of the bar.

Near the forward end the crank pin 24 is squared as at I i8, and a cam |20 having :a square opening is press tted over the square H3 of the crank pin and additionally held by the nut IIE, whereby the cam |20 may not rotate with respect to the crank disc 2t but will be carried around by the crank pin as the crank disc revolves about the center of the main power shaft 22. At a quarter turn of the crank disc 2c clock wise past top center, the high point of the cam I2@ will be directly under the roller |94, whereby the .sliding bar |64 will be at the uppermost position with respect tcl the main connecting rod Sli, whereby the disc valve gli will b e held at maximum open position by the auxiliary connecting rod im. When the crankdisc 25 has .returned the crank pin 2,4 to bottom center, the roller II4 will again be on the low part of the cam i2@ where it will dwell while the crank disc 2t turns further clockwiseto .move the crank pin 2d from bottom center to top center.

The outer working surface .of the cam .|20 is so formed .that the disc valve 94 opens rapidly as soon as the lpiston .8D Starts .on the downward stroke but is closed just as the piston reaches bottom center and remains closed until the `piston returns to top. center.

Mounted on the upper open side of the cylinder 'i6 and fastened thereto by bolts |22 (see Fig. 4:) is a platen .|24 which completely .closes the top of the cylinder except for a slot I 2B which extends through the platen lengthwise thereof, i. e., in the direction which the print paper ISI moves in passing through the machine. Rollers |25 (seev Fig. 1) are rotatable on rods |33 supported in ears |32 formed on the ends of the platen. Rollers |28 carry the print paper over the ends of the platen.

Brackets |34, fast on the bottom of the hollow table I6, carry driving rollers |36 and |33 (see Figs. 1 and 4b) which respectively move the print paper into and out of the machine. The paper supply spool |39 is carried on a bracket Mil fast to the side of the pedestal it. A bellcrank |33 pivoted at |35 has a roller` |31 .at the outer end of one arm which rests on the periphery of the paper roll |35, and a mercury switch M3 yat the outer end of the other arm which tilts to the on position to light a .signal light 155,5 (see Fig. 8) when the roll has decreased to a predetermined diameter. Swinging` brackets Mil carry paper tension rollers M2 and M14. Agravity operated take-up roller Mt is provided at the input end of the machine to allow variation in the loop |41, and a power operated take-up roller |48 at the output .end to allow variation in the loop |49.

Roller |48 rotates on a shaft |50 which is carried on the free end of an arm |52, the other end of the arm having a counterbalancing weight |53 (see Fig. 4b) and, intermediate the ends, having bearing on a stud |54 supported by the hollow table i5. A countershafty |55 has rotative bearing in brackets |58. A crank le), having a stud |62 and roller .ltd at the free end, is fast on the countershaft |56. An angle bracket |66 has one side attached to the side of the arm |52 by screws |67 in such a position that during the interval that the crank |60 rotates clockwise one half` turn from top center to bottom center, the roller `|64 engages the laterally projecting part of the angle bracket and moves it and the arm |52 downward, thereby drawing the print paper downward with the roller |48 into a loop |49 which, together with continuous rotation of the power feed-out roller` |38 moves the exposed section .of `print paper off the platen and draws a new section into its place for the next exposure. Since the power feed-in roller |36 does not bring the paper in fast enough, the loop |41 shortens by raising the weighted take-up roller |46. At .down center the small roller |64 rides off the angle bracket |66 whereby the paper power feedout roller |38 takes up the loop |49 while the papelon they platen remains stationary for the next exposure.

A one to one ratio chain-and-sprocket drive |68 connects the countershaft |56 to the main power shaft 22 and similar chain-and-sprocket drives and |12 connect the countershaft |56 to the power feed-in and power feed-out rollers |36 and |38 respectively.

Mounted on top of the table |6 and secured thereto by screws |14 is an exposure housing |16, the front of which is open and the end walls |15 of which have the underside |11 overhanging toward the front in the form of the half of an arch, the front and so much of the ends being open for the insertion and withdrawal of the lm carrier |18. The film carrier |18 consists of a bottom in the form of a frame |80 (see Fig. 4) with upwardly extending end walls |82, the upper edges of which are of convex contour and shaped to correspond to the overhanging half arch in the end walls of the exposure housing |16. The film supporting glass |84 is held in the frame |80 by clamping strips |86. Spools |88 for the film |94 (see Fig. 1) are rotatably supported on brackets |90 carried Aby the end walls |82 of the film carrier |18. Small rollers |92 (see Fig. 5a) are positioned where the lm |94 rides off the end of the film supporting glass or printing plate |84, the shafts |96 of the rollers |92 having rotative bearing in hinge ears |98 which are formed by bending a portion of the glass clamping strips |86 as shown. A pair of hinge ears 200 on the carrier frame |80 (see Fig. 4) cooperate with a pair of hinge ears 202 on the platen |24 in supporting a hinge rod 204 upon which the film carrier 18 may be rocked inward as in Fig. 5 to place the film |94 and the film supporting glass or printing plate |84 down over the platen |24 for exposure, or rocked outward as in Fig. 'l to place the film |94 and glass |84 in a vertical plane for inspection and dodging of the film. Handles 206, one on each end Wall |82 are provided for rocking the film carrier to one or the other of its positions. In order to provide an adequate light seal where the convex upper edge of the film carrier end walls |82 join the arcuate underside |11 of the end walls of the exposure housing' |16, the housing wall is flanged inward as at 208 and the carrier wall is flanged outward as at 2|0 (see Fig. 6). Stops 2|2 on the film carrier frame |80 engage corresponding stops on the table I6 outside the film width to delimit the thickness of the space 2|3 through which the lm and the print paper must pass. The 'space 2|3 should be finally determined by experiment but may preferably be three or four one vthousandths of an inch greater than the 6 Stops 2|4 on the hinge ears 200 limit the extent to which the film carrier |18 may be withdrawn from the exposure housing |16 so as to position the lm and glass in the vertical position.

The main lamp housing 2|6 is open at the bottom only, the opening being provided with a narrow flange 2|8 which extends completely around it and which seals against light leakage between the upper surface of the glass frame |80 and the main lamp housing 2|6 when the main lamphousing is swung inward to the exposure position, and seals against light leakage between the main lamp housing 2|6, the lm carrier |18, and the exposure housing |16 when the main lamp housing 2|6 is swung outward to the dodging position. A series of lamps 2|9 within the main lamp housing 2|6 (see Figs. 5 and 8) each is provided with an individual rheostat 22|. A single reactor 223 is also placed in the light circuit to control the overall illumination after it has been brought to uniform density over the entire lilm surface by controlling the individual rheostats. A frame 220 is hinged to the exposure housing |16 at 222. Frame 220 carries a viewing glass 224. A mirror 226 is hinged to the exposure housing at 228 and may be swung either upward and latched in that position by the latch 230 or downward as at 232 when it is to be used to view the film |94.

Extending upward from the rear of the exposure housing |16 is a clamp 234 which adjustably clamps a tubular support 236 for supporting a holder 238 for a photo-flash light 239. A circular curtain 240 of black cloth connects the photo-flash light holder to an annular rib 242 in the top of the exposure housing |16. The annular rib 242 is provided with a groove 244 whereby a spring ring 246 may retain the curtain 248 in place subject to removal for removing the bulb 239 in the flashlight holder 238. A slot 241 extends through the exposure housing |16 below the annular rib 242 for insertion of a filter 249 when using the photo-flash light 239.

A series of photoelectric cells 248 are carried on the rear wall on the inside of the exposure housing |16. When the main lamp housing 2|6 and the iilm carrier |18 are swung out to the dodging position as in Fig. 7, and the mirror 226 is raised, these cells measure the intensity of the light after it has passed through the iilm. The intensity of the light received by the photoelectric cells is measured on an ammeter 225, Fig. 5, and correction to the known light requirement is made with the reactor 223.

The operation of the machine is as follows:

A spool |39 of print paper |3| is placed on the bracket |4| and threaded through the machine as shown. A spool |88 of negative iilm |94 is placed in position as shown and the spools turned manually until the desired negative appears in the exposure housing |16. The main lamp housing 2|6 and the lm carrier |18 are tilted outward toward the operator as in Fig. '1, and the mirror 226 is in the lowered position 232. The selected negative is now ready to be inspected for dodging and for adjusting the lamp current which, when passed through the lm, will provide the desired illumination on the paper being used.

The rheostats 22| of all of the lights 2|9 in the main lamp housing 2|6 are now turned on full and the selected negative is viewed by looking through the glass 224 into the mirror 226 where the reflection of the negative will appear.

combined thickness of the Vprint paper and nlm. Dodging is now resorted to, that is, where spots in the nlmseem'l to be too.` brightly illuminated the.- lamps overfthose spots. are. properly dimmed until even illuminationv is. provided. throughout the negative. Themirmr 226 is. now raised to its upper. position whereupon. the photoelectric cellsv 248. receive. the light. which the negative has permitted to' pass and register. its'. intensity on the. ammeter. The reactor. 223 is now ad.- justed until they ammeter. indicates the: illunnnaztion dictated by experience to be. correct for the print paper being. used. The lm carrier |18. and` the main lamp housing 216Y are then tilted. inward away fromv the. operator into the exposure position as.` indicated in phantom. in Fig.. 7i andthe motor started'. by turning on the manual, switch 3:2: whereby each:` turn of. the crank disc 26 will expose a new section of print paper to the: negative and, coincidentally light the lamps in the lamp. housing 2I'6 until the required. number of. .printsA are made If, uponviewing the negative, it is. found that no. dodging is required, the exposure may. be made with the photo-flash light 239 preferably by iirst turning all. of the rheostats 22| in the main lamp housing 216 on` full, measuring with an ammeter. the intensityv of. the light after it has; passed. through thefilm. |94, subtracting the measured intensity from. the known intensity requirement to determine the excess light,v then selecting and placing a lter 249 having.' light reducing capacity equal to the excess. light to reduce the` light reaching: the paper to the ree quired amount. When the ash light is thus used, the main lamp housing. 2l6 remains tilted toward thexoperator outsidethe exposure housing |16, the nlm carrieris'swung; inward; to the exposure position, and theA mirror 226 is. in the down position 232 all as seen in Fig. 5. The photo-flash light providesl a pointilight source which is preferable where dodging. is not necessary.

Whether thel maini lamp housing or thei flash light is employed. automatic repetitionof exposures will` continue' as long.; asfthe manualiswitch 32 remains closed.

As the pistons starts onthe up stroke, the'disc valve Sility closes, whereupon a steady flow of air is forcedout througlithe slot lvZ of thefplaten l24,andA laterally through the space 2l3"between the' las, print paper it, andtheiplaten |24 during theV entire up strokethereby smoothing out the print paper iland film 194m all directions from the: center but particularly crosswise of the film wherel the'Y tension rollers have very little smoothing out eifect.

During each'upstroke of the piston 8l), oneL or the other of thecam lobes33- or Sli-acts oni-amer.- cury switch 35' or 3E- toenergize either theflash light 239- or theV banky of lights 2li-9 in the lamp housing ZIB whichever has been selected by the manual-switch 4 l..

When the f piston Siibegins--its' down` stroke the valvetll starts to openwhereby-thepiston may descend 'without creating suction backwardly through the slot i125 of the platen 124,which might not only-ruine. the print. paper-but.` might interfere with its being drawn forward by the arm 52 and-roller. M8 which alsof'operateon the down stroke.

When thedesired number A- of exposures` have been, madey` the manual switchY 32v should be opened. This Vmay .be-accomplished manually'or by meansof .a convent-ionalcounting mechanism; In either'eventthe. piston 8U. will .comete a stop the` next. timeit reaches top center.. f

If inrpreparing. the machine for operation, it becomes -desirablefto move any part of theprint paper Vthrough the machine without having the piston move up and down, this may beaccomplished by throwing the' handle 48 around 180 degrees, whereupon the paper feed mechanism will continue to function without operating. the piston or: exposure. lights.

Having; described an embodiment of my inven-tion',-

I claim:

1.- In a photographic printing machine; an exposure light, a transparent printing plate spaced from. said light. a pair: ofV filml spools. oneV at each end of. said printing: plate` positionedfor tautening @section oflin across that side of saidprinting plate' opposite said' light, a, platen. slightly spaced apart from said printing plate. on the. side opposite said. light. the: interfacing surfaces'. of saidipla't'e andplaten beingip'arallel planes; spaced apart.l a. distance slightly greater than. the' com"- bined. thickness of the` nlm. andA the". paper,.r011e`r means at. the ends of. said. platen; for; alternately moving and tautening a lengthoii sensitized print paper inthe spacehetween saidplate and platen, an. elongated passageway through. said platen positioned medially and extending lengthwise thereof. in the: direction of movement of said paper, means to flash said; exposure light.- and means `to coincidentally force a substantially steady. iiow of. air throughv thel passageway in said platen against said section: of paper and moving. itv transversely of said section of paper and of saidnlm `from the middle to'and beyond the: edges', whereby theVV lrn and paper are tautened transversely of their length.

2. In. a photographic. printer, a transparent printing plate; exposure light means'on` one; side of said printing platemeans'to hold'a lnr against theA other: side of said. printing. plate; al platen parallel to: and slightly spacedifron'rsaid. printing plate'1olier means at the ends of. theplaten for alternately moving and' tautening a section of. a roll of sensitizedfprint paper Vin the'sp'acebetween said platen andfsaid'lm, said space being slightly greater thanthe thicknessof the' and paper taken tcgethen, an elongated passageway through said' platenme'diallyY positioned' and extending lengthwise thereof in the` direction of movement ofv said papenpowermeans to'ash said" exposure light and coincidentallyA force a substantially steady flow of air through said p'assagewayin said platen andi moving it f transversely of saidr paper from the middleto.Y andV beyond the edges, and sequentially operating saidc roller' means to move said paper lengthwiseYV thereof tov an unexposed portion'ofi the roll. Y

3. In a photographic printen. ai transparent printing plate,` an exposure lamp on one side of 'said-printing plate, means to--holdv a lm against theother side of saidprinting. plate,V a' platen parallel te and. having one side slightly spaced from saidprinting plate; roller means atthe end ofthe platenforalternately moving-t and-.tauteningaa sectionofa r-oll of. sensitizedfprintv paper in. the. spacebetweenI saidplaten and f said` film, said space being slightly greater than the com.- binedthickness of saidr nlmvand said fpaper,V an opening in the'form of Van elongated passageway through said platen medially positioned and ex= tending. lengthwise thereof in the direction of movement ofA saidrpaper, a cyiinder ont'he other side ofsaid .platen-encircling said passagewafa pistoninesaid cylinder,andpowerv operated' means to1 simultaneouslyl Y flash Asaid exposure lamp f and move said piston in said cylinder toward said slot, to thereby force a substantially continuous iiow of air from the middle outward between said platen and said paper whereby said paper is smoothed sidewise from the middle outward and held firmly against said illm.

4. In a photographic printer, a transparent printing plate, an exposure lamp on one side of said printing plate, means to hold a film against the other side of said printing plate, a platen parallel to and having one side slightly spaced from said printing plate, paper control means beyond the ends of said platen constructed and arranged for alternately tautening a section of a roll of sensitized print paper in the space between said platen and said lm then moving it therethrough, said space being slightly greater than the combined thickness of said film and said paper, an elongated passageway through said platen medially positioned and extending lengthwise thereof in the direction of movement of said paper, a cylinder fast on the other side of said platen encircling said passageway thereby making of said passageway a port in the end of said cylinder, a piston in said cylinder movable toward and away from said port, power operated means to move said piston in a direction away from said platen and coincidentally operate said paper control means to move said paper to a new position, and to operate said paper control means to tauten said paper and move said piston toward said platen, whereby a puff of air is discharged through said slot into and through said space whereby said paper is smoothed from the middle outward toward the edges and held firmly against the film during the exposure period.

5. In a photographic printer, the combination of associated elements comprising, a transparent printing plate, exposure light means spaced apart from one side of said printing plate, means to hold a nlm against the other side of said printing plate, a platen parallel to and having one side slightly spaced from said printing plate, paper control means beyond the ends of said platen adapted for alternately endwise tautening a section of a roll of sensitized print paper in the space between said platen and said lm then moving it therethrough, said space being slightly greater than the combined thickness of said film and said paper, a passageway in the form of an elongated slot through said platen medially positioned and extending lengthwise thereof in the direction of movement of said paper, a cylinder secured pressure tight to the other side of said platen encircling said passageway thereby making said passageway a port in said cylinder, a piston in said cylinder movable toward and away from the port in said platen, a connecting rod having one end connected to said piston, a crank operatively connected to the other end of said connecting rod, power means for rotating said crank to operate said piston whereby, when said piston moves in said cylinder toward said port a continuous now of air is forced through said port and said space to thereby crosswise tauten said print paper, and means operated by said power means for lighting said exposure liglt means on the compression stroke of said piston and for operating said paper control means to advance said paper on the suction stroke of said piston.

6. An automatic photographic printer, which comprises a series of associated elements including a transparent printing plate, exposure light means spaced apart from one side of said printing plate, means to hold a photographic film against the other side of said printing plate, a platen paralle1 to and having one side slightly spaced from said printing plate, paper control means beyond the ends of said platen adapted for alternately tautening a section of a roll of sensitized print paper in the space between said platen and said film then moving it therethrough, said space being slightly greater than the combined thickness of said nlm and said paper, a passageway in the form of an elongated slot through said platen medially positioned and extending lengthwise thereof in the direction of movement of said paper, a cylinder secured pressure tight to the other side of said platen encompassing said passageway thereby making of said passageway a port in said cylinder, a piston in said cylinder movable toward and away from the port in said platen, a crank, a crank pin, a connecting rod connecting said crank pin to said piston, power means to rotate said crank to move said piston toward and away from the port in said platen movement of said piston toward said platen causing a continuous flow of air through said port and said space to thereby tauten said paper crosswise of the direction of print paper movement,

' power actuated mechanism to flash said light coincidentally with the compression stroke of said piston and to operate said paper control means to move said paper coincidentally with the suction stroke of said piston.

7. An automatic photographic printer, which comprises, in combination, a series of associated elements including a transparent printing plate, exposure light means spaced apart from one side of said printing plate, means to hold a photographic film against the other side of said printing plate, a platen parallel to and having one side slightly spaced from said printing plate, paper control means beyond the ends of said platen adapted for alternately tautening a section of a roll of sensitized print paper in the space between said platen and said film, then moving it therethrough, said space being slightly greater than the combined thickness of said film and said paper, a passageway in the form of an elongated slot through said platen medially positioned and extending lengthwise thereof in the direction of movement of said paper, a cylinder secured pressure tight to the other side of said platen with its bore encircling said passageway whereby said passageway becomes a port in said cylinder, a piston in the bore of said cylinder movable toward and away from the port in said platen movement of said piston toward said port causing a continuous flow of air from said cylinder through said port and through said space to the atmosphere, whereby said print paper is tautened crosswise of its movement, opposite ends of said piston being connected by an opening, valve means to close said opening, valve closing means associated with said valve means for causing said valve to close on the compression stroke of said piston and to open on the suction stroke, and electric power driven crank mechanism, a connecting rod joining said crank mechanism to said piston, power connection on said crank mechanism for flashing said exposure light means on the compression stroke of the piston, for operating said paper control means to advance said paper on the suction stroke of said piston, and

' for opening an electric switch to disconnect said electric power at top center of the piston.

8. An automatic photographic printer, which comprises, in combination, a transparent printing plate, exposure light means spaced apart from fil one side of vsaid printing plate, means to hold Aa photographic lm against the other side of Vsaid printing plate, a ,platen parallel to and having one side slightly spaced from said printing plate, paper control means beyond the ends of said platen adapted for alternately tautening a section Aof a roll of sensitized print paper Yinthe space between said platen and said lm, then moving it therethrough, said space being slightly greater than the combinedjthickness oi saidfllm and said paper, a passageway in the form of an elongated slot through said platen medially positioned and extending lengthwise thereof in the direction of movement of said paper, a cylinder secured pressure tight to yhe other side of said platen the bore of said cylinder encircling said passageway whereby said passageway becomes a port in said cylinder, `a piston in said cylinder movable toward and away from the port in said platen adapted, when said piston moves toward said port to cause a continuous flow of air to pass through said port and said space vto thereby tantensaid print paper crosswise of the direction of dits travel, opposite sides of said piston being connected Vby ,an opening, valve means to close said opening, an `electric power driven crank mechanism, ia connecting rod joining said crank mechanismto said piston, power connections on said crank mechanismV for causing said valve to close onthe compression stroke of said piston and to open on the suction stroke, for flashing ysaid exposure light means on the compression stroke, for operating said paper control means to advance said paper on the suction stroke, and for opening an electric switch to diseonnectsaid electric power at top center.

9. A continuous ,photographic printer. which comprises. Combination. a transparent printing plate, exposure light means spaced apart from one side of `Vsaid printing plate, means to hold a pjhOtOgraphic film against the other side of said printing plate, Aa platen parallel toand having one side slightly spaced from said printing plate, paper control means beyond the ends of said platen adapted for `alternately tautening Aa section of a roll of sensitized print .paper in thespace between said platen .and said iilm, then moving it therethrough, said space being slightly greater than the combined thickness of vsaid film and saidI paper. a passageway in the form .of an elongated .slot through said platen medially positioned and extending lengthwise thereof in the direction of `rrioveinent oi said paper, a .cylinder secured pressure tight to .the other side of said platen encircling said passageway thereby forming of s aid passageway a port for said cylinder, a piston in the zslot in said cylinder movable toward and away from said ,platen adapted, when `said piston moves toward said port to cause Aa, continuous 119W of through said port ,andlateraily through` saidspace to thereby tautensaid print paper CrQSSWSe of its movement, YOpposite sides 0f Said piston being connected by an opening, valve means to close said openingen electric power driven crank mechanism, a connecting rod ljoining said crank mechanism tosaid piston, cams operated` by said crank mechanism for closing said Valve and flashing said exposure light means on the compression stroke of the piston, for opening said valve and operating said paper control d0 12 means to `advance said ,paper on the suction stroke of saidpiston, andior opening an electric lswitch to disconnect said electric power at 'top center of the piston.

10. A continuous photographic printer, which comprises, in combination, a transparent printing plate, exposure light `means yspaced Aapart from one side of said :printingplata means to hold va photographic iiilm `against the other vside of said printing plate, a platenparallel to and having one side slightly spaced from said printing plate, paper control means beyond "the ends of 'said platen adapted for alternately tautening a section of a yroll of sensitized print paper in the V,space between said platen and said Llm, "th-en moving it therethrough, said .space `4being slightly greater than the combined thickness of said nlm and said paper, a passageway in the `form of an elongated slot through said platen medially'positioned and extending lengthwise thereof inthe direction of movement .of s aid paper, a cylinder secured pressure tight to the other side of said platen the bore of said cylinder encircling said passageway whereby said passageway Vforms a portfor said cylinder, a piston in said lcylinder movable .toward and Vaway from the slot in said platen, adapted, when said piston. Amoves toward said port, to Aprovide a continuous flow of air through said port `4and through said space 'to crosswise tauten said print paper, opposite sides of said piston being connected by an opening, Valve means .to closesaid opening, an` electric power source, a crank .mechanism .adapted .to be driven by said power source, a connecting Irod joining said crank mechanism to said piston,.cams operated by Vsaid crank 'mechanism for closing. said valve and flashing s aid exposure light .means on the compression stroke of the piston, for opening said valve and operating saidpaper control means to advance said vpaper on the .suction stroke .oi said piston, 4and for opening an electric .switch to Adisconnect said .electric power `at top center of the piston, and manual 4means to selectively connect or disconnect said .power unit from said crank mechanism.

WILLIAM H. RICHARDS.

REFERENCES CITED The following references are of record in the iile of this patent:

v 'UNITED STATES PATENTS Number Name Date 1,013,033 Marquis Dec. 26, 1911 1,044,028 Curtiss iNov. 12, A1912 1,200,753 Neff Oct. 10, '.1916 .1,429,723 Eason Sept. 19, '1922 1,598,756 Troland Sept. 7, 1926 V1,711,333 Swenson Apr.30, 1929 1,738,095 Carleton Dec. 3 1929 1,828,364 Garbutt Oct. 201, 1931 1,981,406 Young Nov. .20, 1934 2,047,474 Howell July 14, 1936 2,144,088 Scott Jan. 17, 1939 2,206,333 Robertson July 2, 1940 2,291,613 Dye sa Aug. 4, 1942 2,331,451 Blaney Oct. 12, 1943 2,349,999 Urbach May 30, 1944 2,380,962 Garraway Aug. 7, 1945 2,413,218, Coroniti Dec. 24, 1946 

